Method of forming structure having surface roughness due to nano-sized surface features

Abstract

A method of forming a micro structure having nano-sized surface features is provided. The method includes the steps of forming a micro structure having predetermined size and shape on a substrate, coating a carbon polymer layer on the substrate including the micro structure to a predetermined thickness, performing a first etch on the carbon polymer layer by means of plasma etching using a reactive gas in which O 2 gas for etching the carbon polymer layer and a gas for etching the micro structure are mixed and forming a mask layer by the residual carbon polymer layer on the surface of the micro structure, and performing a second etch by means of plasma etching using the mixed reactive gas to remove the mask layer and etch the surface of the micro structure not covered by the mask layer so that the micro structure has nano-sized surface features.

What is claimed is:  
     
       1. A method of forming a micro structure having nano-sized surface features, the method comprising the steps of: 
       forming a micro structure having predetermined size and shape on a substrate;  
       coating a carbon polymer layer on the substrate including the micro structure to a predetermined thickness;  
       performing a first etch on the carbon polymer layer by means of plasma etching using a reactive gas in which O 2  gas for etching the carbon polymer layer and a gas for etching the micro structure are mixed and forming a mask layer by the residual carbon polymer layer on the surface of the micro structure; and  
       performing a second etch by means of plasma etching using the mixed reactive gas to remove the mask layer and etch the surface of the micro structure not covered by the mask layer so that the micro structure has nano-sized surface features.  
     
     
       2. The method of  claim 1 , wherein the carbon polymer layer is formed of polyimide or photoresist. 
     
     
       3. The method of  claim 2 , wherein the carbon polymer layer is etched using reactive ion etching (RIE). 
     
     
       4. The method of  claim 1 , wherein the carbon polymer layer is etched using reactive ion etching (RIE). 
     
     
       5. The method of  claim 4 , wherein surface characteristics of the nano-sized surface features are controlled by adjusting the difference in etch rate between the micro structure and the carbon polymer layer. 
     
     
       6. The method of  claim 5 , wherein the etch rate is adjusted by adjusting at least one of a group consisting of: plasma power, the O 2  content of the reactive gas with respect to the etch gas for etching the micro structure and a plasma process pressure. 
     
     
       7. The method of  claim 4  wherein the micro structure is formed of one or a mixture of two or more material selected from the group consisting of: molybdenum (Mo), tungsten (W), silicon, and diamond, and the reactive gas is a mixture of O 2  gas and fluorine-family gas. 
     
     
       8. The method of  claim 7  wherein the reactive gas comprises at least one gas selected from a group consisting of: CF 4 /O 2 , SF 6 /O 2 , CF 4 /SF 6 /O 2 , CF 4 /CHF 3 /O 2 , and SF 6 /CHF 3 /O 2 . 
     
     
       9. The method of  claim 4  wherein the micro structure is formed of one or a mixture of two or more materials selected from the group consisting of: molybdenum (Mo), tungsten (W), silicon, and diamond, and the reactive gas is a mixture of O 2 gas and chlorine-family gas. 
     
     
       10. The method of  claim 9  wherein the reactive gas comprises at least one gas selected from a group consisting of: Cl 2 /O 2 , CCl 4 /O 2 , and Cl 2 /CCl 4 /O 2 .